Personal gas supply delivery system

ABSTRACT

A supply of gas such as oxygen is provided to a person in need of such gas supply. The delivery system includes an alarm to alert the recipient of the gas or another when and if the gas supply is disrupted. The alarm system preferably includes a reset and on-off switch that is recessed sufficiently to prevent accidental disabling of the alarm system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The purpose of this invention is to employ a gas flow alarm in apersonal gas supply delivery system.

2. Description of the Art Practices

Hospitals, nursing homes, dental offices, clinics and a number of otherhealth care institutions utilize medical gasses in rendering care topatients. It is well known to administer oxygen, air, and nitrous oxideto patients for treatment of a variety of different conditions or duringsurgical operations.

A number of medical institutions now employ medical gas systems whichuse a central gas supply source for providing a positive flow of medicalgasses. These systems often utilize a network of conduits or supplylines to deliver the medical gas remote from the central source of themedical gas. The networks often include main and branch shut-off valvesto enable isolation of a portion of the network in the event of damageor fire, or to effect needed repairs.

The lives of patients may depend on receiving a reliable source of themedical gas, a real need has developed to ensure that the medical gassystem is functioning properly, and to annunciate an alarm in the eventa malfunction or alarm condition is detected. Such conditions may occur,for example, when the shut-off valve is either partially or fullyclosed. In such circumstances, the necessary supply of gas may beinsufficient or non-existent.

A further inadvertent interruption of the medical gas supply may occurwhen the medical gas is humidified. Commonly employed humidifyingsystems utilize a threaded plastic vessel that is screwed into athreaded plastic cap. If the threads of the threaded plastic vessel orthreaded plastic cap are damaged or misaligned the medical gas may belost to the surrounding environment with the consequent non-delivery ofthe medical gas to the patient.

There is a further need to detect other defects in the system that mayimpair the medical gas system effectiveness. For example, usage of thesystem may eventually result in low pressure conditions in the supplytank when the supply of gas is nearly exhausted. There is a further needfor early detection of these problems so that replacement sources ofmedical gas may be provided to the patient before the medical gasdelivery system becomes completely inoperative.

Finally, due to the escalating costs associated with medical care andthe shortage of trained nurses and technicians, monitoring of themedical gas delivery systems should be easy and capable of instantrecognition of system faults. In particular, the recipient of themedical gas or a visitor of the patient should be able to recognizesystem faults.

Several methods using various apparatus have been employed to determineif a supply of a gas is within operating parameters. Such methods andaparrati are disclosed below.

U.S. Pat. No. 6,067,022 granted to Laswick, et al., on May 23, 2000describes an in-line low supply pressure alarm device powered solely bysupply flow of pressurized gas from a gas supply for providing an alarmsignal when supply gas pressure is below a selected minimum pressure.The alarm device includes a manifold having an input port forcommunicating with the supply gas supply, an output port for conductingthe gas downstream and a manifold chamber disposed therebetween.

The Laswick, et al., patent utilizes gas powered alarms such as anaudible reed alarm or a visual pneumatic alarm are connected to themanifold chamber via an alarm supply conduit, and produce an alarmsignal when pressurized gas passes to the alarms. According to theLaswick, et al., patent a supply gas pressure sensor, in communicationwith the manifold chamber, produces an actuating flow of pressurized gasby activating a pressure switch, in response to sensing of an supply gaspressure below the selected minimum pressure.

U.S. Pat. No. 6,067,022 to Laswick, et al., further provides a pneumaticalarm output switch, in the alarm supply conduit and in communicationwith the pressure sensor and pressure switch via an actuation conduit,controls gas flow to the alarms in response to the actuating flow. TheLaswick, et al., patent preferably includes an alarm oscillation systemis included for alternating the direction of the actuating flow to andfrom the alarm output switch, to open and close the alarm output switchthereby turning the alarm on and off in a cyclical fashion.

U.S. Pat. No. 4,674,321 issued to Joshi on Jun. 23, 1987 describes aleak detector employing an ion-conducting membrane is disclosed. TheJoshi patent describes an oxygen-ion conducting membrane which employs ahigh vacuum on one side is used to detect very small quantities ofoxygen flowing through a minute fissure in a part to be tested forleaks. The Joshi patent further describes an oxygen-ion conductingmembrane which is biased with direct current voltage to driveoxygen-ions through the membrane away from the high vacuum side.

U.S. Pat. No. 3,133,997 to Greene issued May 19, 1964 describes afluid-pressure activated switch Pressure activated switches aredescribed in the MPL publication available at mpl@pressureswitch.com 555SW 12th Avenue Pompano Beach, Fla. 33069. Further disclosures ofpressure activated switches are found at World Magnetics 810 HastingsStreet Traverse City, Mich. 49686, telephone: 231-946-3800 and fax:231-946-0274 and located on the web at http://www.worldmagnetics.com.

U.S. Pat. No. 5,057,822 to Hoffinan issued Oct. 15, 1991 describes amedical gas alarm system is provided which includes a sensor unitpneumatically connected to a medical gas supply line and a switchconnected to a valve in the supply line for detecting the open conditionof the valve.

In the Hoffinan patent, in the event either the sensor detects a highpressure or low pressure condition in the supply line or closing of thevalve activates the switch, an alarm signal is received by an alarmmodule and an alarm is activated. The alarm of the Hoffman patent may bevisual, audible or both. During normal operations, the alarm module ofthe Hoffman patent displays both a system on condition and a digitaldisplay indicating the pressure in the supply line.

The Hoffinan patent also includes a method of monitoring the conditionof a medical gas delivery system which includes sensing the pressure inthe gas supply line, detecting the open condition of the valve,transmitting an alarm signal to an alarm module in response to alarmconditions detected either as a result of improper pressure or valveclosure, and generating a humanly perceptible alarm warning in responseto receipt of an alarm signal.

Fukui in U.S. Pat. No. 5,457,333 issued Oct. 10, 1995 describes a gassensor comprises a precious metal electrode, a semiconductor layerentirely or partly covering the precious metal electrode, a barrierlayer having a high potential formed at an interface between theprecious metal electrode and the semiconductor layer. The Fukui patentrecites a gas sensor for use in a leak detector for detecting a fuel gassuch as town gas, the sensor comprising a precious metal electrode; anda semiconductor layer at least partly covering said precious metalelectrode, wherein the semiconductor layer includes, as a maincomponent, at least one substance selected from the group consisting oftin oxide, zinc oxide and indium oxide. The Fukui patent precious metalelectrode is formed of a substance selected from the group consisting ofplatinum, gold, ruthenium, lead, silver, iridium, and alloys thereof andhas a barrier layer having a high potential formed between said preciousmetal electrode and said semiconductor layer and on a surface of saidprecious metal electrode. The barrier layer described in the Fukuipatent comprises either a substance formed by electrodeposition andselected from the group consisting of platinum, palladium, gold andrhodium, or a substance formed by thermal decomposition and selectedfrom the group consisting of platinum, palladium and gold, said barrierlayer being capable of enhancing sensitivity to isobutane gas relativeto other gases.

U.S. Pat. No. 5,293,866 issued to Padula Mar. 15, 1994 provides adescription of an indicator device which can be attached to a standardoxygen flow meter is disclosed. The indicator device described in thePadula patent has a rod along which a pointer can be moved and lockedinto position. The pointer in the Padula patent can be set at the oxygenflow level prescribed by the physician as indicated by the scale on theoxygen flow meter. If the oxygen flow level, as described in the Padulapatent, is changed or if oxygen is discontinued for any period of time,the attendant can then set the oxygen flow to the prescribed level bycontrolling the valve on the oxygen flow meter so that the float, whichindicates oxygen flowing liters per minute is positioned opposite theposition of the pointer. The foregoing mechanism recited in the Padulapatent prevents erroneous or improper setting of oxygen flow levels topatients after interruption or change of oxygen flow level, which can bedangerous, and life threatening.

To the extent that the foregoing references are relevant to the presentinvention, they are herein specifically incorporated by reference. Wheretemperatures are given, they are in degrees C. unless otherwiseindicated. Pressure measurements are reported in KPa. Percentages andratios given herein are by weight unless otherwise indicated.Measurments herein are stated in degrees of approximation and whereappropriate the word “about” may be inserted before any measurement.

SUMMARY OF THE INVENTION

The present invention describes a personal gas supply delivery systemcomprising:

-   -   a first conduit, for when in use receiving a supply of a gas at        a first pressure from a first gas supply line,    -   said first conduit connected with a gas flow alarm, said gas        flow alarm for when in use for determining an instantaneous        difference in the pressure or volume of the gas per unit of time        and the volume of the effluent gas per unit of time,    -   a second conduit connected with said gas flow alarm, for when in        use receiving the supply of gas through said gas flow alarm,    -   said first conduit having a first connector, for when in use        providing a detachable airtight seal with a compatible connector        on the gas supply line, said first connector located distally        from said gas flow alarm, and    -   said second conduit having a second connector, for when in use        providing a detachable airtight seal with a compatible connector        on a second gas supply line,        said second connector located distally from said gas flow alarm

The present invention further describes a personal gas supply deliverysystem comprising:

-   -   a moisturizing vessel, for when in use, having the capability to        contain a liquid to provide a source of moisture to increase the        amount of moisture in a gas passing through the liquid,    -   said moisturizing vessel having a first opening for receiving an        influent gas,    -   said moisturizing vessel having a second opening for an effluent        gas,    -   a first conduit connected with said second opening, said first        conduit for when in use, for receiving the effluent gas,    -   a gas flow alarm connected with said first conduit, and    -   a second conduit connected with said gas flow alarm said second        conduit in fluid communication with said first conduit,        said gas flow alarm for determining the instantaneous pressure        differential of the influent gas and the effluent gas.

Yet a further embodiment of the invention is a personal gas supplydelivery system comprising:

-   -   a moisturizing vessel, for when in use, having the capability to        contain a liquid to provide a source of moisture to increase the        amount of moisture in a gas passing through the liquid,    -   said moisturizing vessel having a first opening for receiving an        influent gas,    -   said moisturizing vessel having a second opening for an effluent        gas,    -   a first conduit connected with said second opening, said fist        conduit for when in use, for receiving the effluent gas,    -   a gas flow alarm connected with said first conduit, and    -   a second conduit connected with said gas flow alarm, said second        conduit in fluid communication with said first conduit,    -   said gas flow alarm for determining an instantaneous difference        in the volume of the influent        gas per unit of time and the volume of the effluent gas per unit        of time.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to one skilled in the art to which the present inventionrelates upon consideration of the following description of the inventionwith reference to the accompanying drawings, wherein:

FIG. 1 is a frontal perspective of a finished product embodimentaccording to the invention;

FIG. 2 is a frontal perspective of a part of the finished productembodiment according to the invention;

FIG. 3 is a sectional view of a part of the finished product embodimentaccording to the invention taken along line 3-3;

FIG. 4 is a partial sectional view of the alarm according to theinvention;

FIG. 5 is a frontal perspective of a part of the finished productembodiment according to the invention; and

FIG. 6 is an anterior view of a part of the finished product embodimentaccording to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As best seen in FIG. 1 there is a finished product embodiment accordingto the present invention. A personal gas delivery system 10 includes ahollow flexible tubing 14. The hollow flexible tubing 14 is convenientlyany sufficiently flexible tubing to permit movement without undue riskof crimping, cracking or other damage, which may interrupt the flow of amedical gas.

A suggested hollow flexible tubing 14 is Tygon tubing available fromSaint-Gobain Performance Plastics Corporation PO Box 3660, Akron, Ohio44309. Saint-Gobain may be reached toll free at 800-798-1544 and directat 330-798-9240 or at http://www.tygoncom/.

The hollow flexible tubing 14 is permanently terminated by a hollowtubing connector 18. The hollow tubing connector 18 is convenientlyforced into a nipple connector 24 extending from the gas flow alarm 20.The hollow tubing connector 18 is conveniently detachable from thenipple connector 24 through moderate hand pressure with a twistingmotion. The hollow flexible tubing 14 is in fluid communication with thehollow tubing connector 18, and the nipple connector 24.

In a typical usage, it is not necessary to employ any lubricant toensure an airtight fit of the hollow flexible tubing connector 18 to thenipple connector 24. Similarly, there is no need for caulking oradhesive to ensure an airtight fit of the hollow tubing connector 18 tothe nipple connector 24.

The nipple connector 24 is made of a rigid plastic such aspolyvinylchloride, polycarbonate. The nipple connector 24 may also bemade of other suitable rigid plastic materials.

The nipple connector 24 is affixed at the opposite end thereof with agas flow alarm 20. The point of attachment of the gas flow alarm 20 tothe hollow tubing connector 18 is by a nipple connector 24 extendingfrom the gas flow alarm 20. The nipple connector 24 is more particularlyshown in FIG. 2. The hollow tubing connector 18 is in fluidcommunication with the first nipple connector 24.

The gas flow alarm 20 is one, which is suitable for low flow rates andrelatively low pressures. Typically, the gas flow alarm 20 is capable ofdetermining the instantaneous pressure differential of a supply of amedical gas in the range of about 0.005 KPa to about 200 Kpa preferably0.013 KPa to about 150 Kpa, (the equivalent of 0.05 in/H₂O as a low endand 550 in/H₂O), above the ambient atmospheric pressure. That is, thesupply of a medical gas will be determined by a flow rate approximatelyequal to the ambient pressure with ambient at see level being 101 KPa(14.7 pounds per square inch).

The low flow rates and relatively low pressures are utilized because thesystem is designed to provide a supplement of a medical gas to a patientrather than forcing the gas into the lungs of the patient. The systemwill work to provide accurate data at elevations from slightly below sealevel to above about three thousand meters (minus 200 feet mean sealevel to about ten thousand feet).

As best seen in FIG. 4, a switch 30 suitable for use in the gas flowalarm 20 has a flexible metallic reed 32. The flexible metallic reed 32is connected at an end 34 to an electrical terminal 36. The electricalterminal 36 is connected to a low voltage current source. The flexiblemetallic reed 32 has second end 40. The second end 40 of theflexible-metallic reed 32 contacts a second electrical terminal 44 tocomplete an electrical circuit. The flexible metallic reed 32 issufficiently flexible enough to permit a relatively low flow(consequently low pressure) of a medical gas to displace (break) thesecond end 40 of the flexible metallic reed 32 away from the secondelectrical terminal 44 thereby interrupting the electrical circuit. Thedirection of the flow of the medical gas according to the presentinvention is shown in FIG. 4 by the double-headed arrows. A set screw 46permits the switch 30 to be variably set to accommodate differentsensitivities for the gas flow alarm 20. The set screw 46 impinges onthe second electrical terminal 44 to place the second electricalterminal 44 in closer proximity to the second end 40 thereby making theswitch 30 more sensitive to gas flow.

Suitable gas flow alarms 20 are described in U.S. Pat. No. 3,133,997 toGreene issued May 19, 1964 that describes a fluid-pressure activatedswitch. Pressure activated switches are described in the MPL publicationavailable at mpl@pressureswitch.com from Micro Pneumatic Logic Inc., 555SW 12th Avenue Pompano Beach, Fla. 33069. Further disclosures ofpressure activated switches are found at World Magnetics 810 HastingsStreet Traverse City, Mich. 49686, telephone: 231-946-3800 and fax:231-946-0274 and located on the web at http://www.worldmagnetics.com.The gas flow alarms described in U.S. Pat. No. 3,133,997 to Greene, theMPL publication from Micro Pneumatic Logic Inc., and the World Magneticsare specifically incorporated herein by reference.

As best seen in FIG. 2, the gas flow alarm 20 has protruding from it asecond nipple connector 52. The second nipple connector 52 is similar inconstruction and design to the first nipple connector 24. The secondnipple connector 52 is in fluid communication with the gas flow alarm20.

A second hollow tubing connector 58 plastic such as PVC orpolycarbonate. The design and construction of the second hollow tubingconnector 58 is similar to that of the hollow tubing connector 18. Thesecond hollow tubing connector 58 is in fluid communication with thesecond nipple connector 52 and accordingly is in fluid communicationwith the gas flow alarm 20.

The second hollow tubing connector 58 is connected with a second hollowflexible tubing 64. The second tubing connector 58 is convenientlyforced into the second nipple connector 52. The hollow flexible tubing64 is in fluid communication with the hollow tubing connector 58. Thesecond hollow tubing connector 58 is conveniently detachable from thesecond nipple connector 52 through moderate hand pressure with atwisting motion.

The suggested hollow flexible tubing 64 is Tygon tubing available formthe same source as the hollow flexible tubing 14. As with the hollowconnector tubing 18, the hollow tubing connector 58 it is not necessaryto employ any lubricant to ensure an airtight fit of the hollow tubingconnector 58 to the nipple connector 52. Similarly, there is no need forcaulking or adhesive to ensure an airtight fit of the hollow connectortubing 58 to the nipple connector 52.

The second hollow flexible tubing 64 is connected with a gasdistributive device 70. The point of the connection of the hollowflexible tubing 64 is connected with a gas distributive device 70 iswith a unitary to binary connector 74. The unitary to binary connector74 connects at the unitary opening 76 to the hollow flexible tubing 64.The unitary to binary connector 74 is in fluid communication with thehollow flexible tubing 64. The second hollow flexible tubing 64 ispermanently connected to the unitary to binary connector 74.

The unitary to binary connector 74 has a binary opening 78 at the enddistal from the unitary opening 76. The binary opening 78 is in fluidcommunication with the unitary opening 76 and accordingly with thesecond hollow flexible tubing 64.

The unitary to binary connector 74 is formed of a hollow tube 82 and asecond hollow tube 84. The first hollow tube 82 and the second hollowtube 84 are conveniently obtained as a co-extruded material. The firsthollow tube 82 and the second hollow tube 84 are typically formed from aflexible material such as the previously discussed Tygon tubing. Thefirst hollow tube 82 and the second hollow tube 84 are each separatelyin fluid communication with the binary opening 78.

A clip 88 is conveniently utilized to maintain the first hollow tube 82and the second hollow tube 84 in close proximity. The clip 88 is a “C”shaped hard plastic into which the first hollow tube 82 and the secondhollow tube 84 are inserted and held in place in the interior curvatureof the “C” by pressure fitting. The clip 88 is with moderate effortslideably engaged on the outer surface of the first hollow tube 82 andthe second hollow tube 84.

The first hollow tube 82 connects with nasal cannula 90 via a firstnasal cannula fitting 92. The second hollow tube 84 with a second nasalcannula fitting 96. The first nasal cannula fitting 92 is in fluidcommunication with first hollow tube 82. The nasal cannula 90 isconnected with a second nasal cannula fitting 96. The second nasalcannula fitting 96 is in fluid communication with second hollow tube 84.

The first nasal cannula fitting 92 and the second nasal cannula fitting96 are a part of the hollow nasal cannula tube 98. The first nasalcannula fitting 92 and the second nasal cannula fitting 96 are both influid communication with the hollow nasal cannula tube 98.

The nasal cannula tube 98 has protruding from it a pair of spaced apartnasal fittings 102 and 104. The spaced apart nasal fittings 102 and 104are in fluid communication with the hollow nasal cannula tube 98.

The spaced apart nasal fittings 102 and 104 have nasal orifices 108 and110. The nasal orifices 108 and 110 permit the flow of a medical gas outof the nasal cannula tube 98 to the nostrils of a patient in need of themedical gas.

A retaining strap (not shown) is conveniently connected with the nasalcannula tube 98. The retaining strap 118 permits the gas distributivedevice 70 to be retained around the neck of the patient while thepatient is receiving the medical gas. To avoid accidental disconnectionand the resultant false alarms, it is suggested that each of the hollowflexible tubing 14 and the hollow flexible tubing 64 be from 25centimeters to 2 meters, preferably 30 centimeters to one meter inlength.

The personal gas delivery system 10 permits the hollow flexible tubing14 to receive a medical gas, such as oxygen, from a medical gas supplysource (not shown). The hollow flexible tubing 14 receives the medicalgas allowing the flow of a medical gas to the hollow tubing connector18.

The medical gas passes through the hollow tubing connector 18 in anuninterrupted flow to the gas flow alarm 20. The medical gas passesthrough the gas flow alarm 20. If the flow rate of the medical gas isbelow a predetermined point then the alarm is activated.

The activation of the alarm may be by an audible signal to alert atleast the patient that the flow rate of the medical gas is below apredetermined point. As the patient may be suffering from a hearingimpairment it is also possible to utilize a visible light to alert thepatient that the flow rate of the medical gas is below a predeterminedpoint.

As the patient may be patient may be suffering from a hearing impairmentand a lack of visual acuity it is also possible to utilize a vibratorymechanism to alert the patient that the flow rate of the medical gas hasfallen below a predetermined point. The vibratory mechanism is leastfavored, as it requires an external power source to avoid prematuredischarge of the batteries.

Each of the alarms, audible, visual and vibratory has disadvantages. Asnoted the audible alarm is of limited value with a hearing impairedpatient. The light activated alarm requires a sighted patient and is oflittle use when the patient is sleeping or when the alarm light ishidden beneath a blanket or other covering. Similarly, the vibratorymechanism as an alarm is of limited value when the patient is sleepingand may be covered with a blanket which may absorb the vibrations whichare intended to alert the patient that the flow rate of the medical gashas fallen below a predetermined point.

If the system is otherwise operating properly the medical gas flowsthrough the gas flow alarm 20, through the second nipple connector 52and into the second hollow tubing connector 58. The medical gas thenflows from the second hollow tubing connector 58, into hollow flexibletubing 64, and from there into the gas distributive device 70.

The purpose of having the flow of medical gas divided into two flowpaths is important in the present invention. As the gas flow alarm 20 isupstream from the nasal cannula tube 90 it possible for any of thecomponents from the gas flow alarm 20 downstream to becomenon-functional, e.g. blocked. For example, one of the pair of spacedapart nasal fittings 102 and 104 may become blocked because of mucous inthe opening the affected nasal fitting.

Similarly, one of the first hollow tube 82 and a second hollow tube 84may be crushed or otherwise blocked. As the present invention permitshaving the flow of medical gas divided into two flow paths at least someof the medical gas passing through one of the hollow tubes will likelyreach the patient. In any other case, the alarm 20 may be fullyfunctional and the patient would still not receive an adequate supply ofthe medical gas.

Thus, as an additional feature to the alarm aspect of the presentinvention is a transmitter 200. The transmitter 200 is shown in FIG. 6.The transmitter 200, when connected with the gas flow alarm 20,transmits the fact that the flow rate of the medical gas has fallenbelow a predetermined point to a remote receiving location such as anursing station. The transmitter 200 is any conventional low powerdevice that does not interfere with the operation of the overall system.The transmitter 200 transmits through an antenna 202.

A second embodiment of the present invention employs the feature ofmoisturizing a medical gas to be supplied to the patient. As best seenin FIG. 5, is a medical gas supply line 210. The medical gas supply line210 is connected with a humidifying vessel 220. The humidifying vessel220 comprises a humidify container 222 and a humming container cap 224.

The humidifying container 222 has a screw sealing mechanism at its upperopening. The humidifying container cap 224 has a screw sealingmechanism. The humidifying container cap 224 has a screw sealingmechanism is mated to the screw sealing mechanism of the humidifyingcontainer 222. The humidifying container cap 224 has extending therethrough a first opening 228. The humidifying container cap 224 hasextending there through a second opening 232.

A gas delivery conduit 236 extends through the first opening 228 in thehumidifying container cap 224. The gas delivery conduit 236 extends intothe humidifying container 222, when the humidifying container cap 224 isscrewed onto the humidifying container 222, to a point just above thehumidifying container lower surface 238. In practice, the gas deliveryconduit 236 will be below the level of the humidifying liquid in thehumidifying container 222.

A gas receiving conduit 242 extends through the second opening 232 inthe humidifying container cap 224. The gas receiving conduit 242,extends into the humidifying container 222, when the humidifyingcontainer cap 224 is screwed onto the humidifying container 222, to apoint just below the bottom 244 of the humidifying container cap 224.When the personal gas delivery system 10 is in operation the gasreceiving conduit 242 will not extend below the level of the humidifyingliquid in the humidifying container 222.

A medical gas is introduced to the delivery conduit 236 and into thehumidifying container 222. The humidifying container 222 is filed to apoint about 2 centimeters below its top with distilled water. The gasdelivery conduit 236 is below the level of the humidifying liquid in thehumidify container 222. The medical gas from the gas delivery conduit236 is humidified in the humidifying container 222.

The gas receiving conduit 242 takes up the humidified medical gas. Thedouble-headed arrows in FIG. 5 show the direction of gas flow. Themedical gas then passes through the gas flow alarm 20 as previouslydescribed.

A third embodiment of the invention is shown in FIG. 6. In the lastembodiment of he invention there is disclosed a switch 300 for the gasflow alarm 20. The gas flow alarm 20 has an anterior surface 302.Located on the anterior surface 302 is a light 304 for alerting thepatient that the gas flow alarm 20 has detected a low pressure or lowflow rate of the medical gas.

To allow the patient to be confident that the gas flow alarm 20 isoperating properly there is an alarm test switch 306. A second switch onthe anterior surface of the gas flow alarm 20 is a reset switch 306. Thereset switch 306 is located on the anterior surface 302 of the gas flowalarm 20. The gas flow alarm 20, when activated will provide acontinuous signal until the alarm is reset, or the alarm is inactivated,or the batteries are depleted.

Accordingly, there is a need to manually reset the alarm when the alarmis activated. When the medical gas supply is intentionally interruptedsuch as to replace the gas supply, to provide services to the patientsuch as bathing the patient, or to replenish the humidifying liquid 242in the humidifying container 222, it is desirable to turn off the gasflow alarm 20. Accordingly, the gas flow alarm 20 may also provide an onoff switch (or a test feature) 310.

Although the above description and accompanying drawings relate to aspecific preferred embodiment as presently contemplated by theinventors, it will be understood that the invention in its broad aspectincludes mechanical and functional equivalents of the elements describedand illustrated.

1-30. (canceled)
 31. A personal gas supply delivery system comprising: avessel, for when in use having a moisturizing liquid, to provide asource of moisture to increase the amount of moisture in an influent gaspassing through the moisturizing liquid to obtain a moisturized effluentgas, said vessel having a first opening for receiving an influent gas,said moisturizing vessel having a second opening for when in use,receiving the moisturized effluent gas, a single first flexible conduitconnected with said second opening, said single first flexible conduitfor when in use, for receiving the moisturized effluent gas, a gas flowalarm connected with said single first flexible conduit, and a singlesecond flexible conduit connected with said gas flow alarm, said secondconduit in fluid communication with said single first flexible conduit,said gas flow alarm for determining the instantaneous pressure or flowvolume of the moisturized effluent gas; and, said single second flexibleconduit connecting with a pair of spaced apart nasal fittings.
 32. Thepersonal gas supply delivery system according to claim 31 wherein thegas flow alarm is set to alert a recipient of the effluent gas by anaudible signal.
 33. The personal gas supply delivery system according toclaim 31 wherein the gas flow alarm is set to alert a recipient of theeffluent gas by a visual signal.
 34. The personal gas supply deliverysystem according to claim 31 wherein the gas flow alarm is set to alertthe recipient of the effluent gas by a vibratory signal.
 35. Thepersonal gas supply delivery system according to claim 31 furthercomprising an alarm reset feature located between said single firstflexible conduit and said single second flexible conduit.
 36. Thepersonal gas supply delivery system according to claim 31 furthercomprising an alarm test feature located between said single firstflexible conduit and said single second flexible conduit.
 37. A methodof permitting a recipient of a moisturizing gas from a personal gassupply delivery system to respond to a condition of an alarm in thepersonal gas supply delivery system comprising: obtaining personal gassupply delivery system having a vessel, said vessel, for when in usehaving a moisturizing liquid, to provide a source of moisture toincrease the amount of moisture in an influent gas passing through themoisturizing liquid to obtain a moisturized effluent gas, said vesselhaving a first opening for receiving an influent gas, said moisturizingvessel having a second opening, a single first flexible conduitconnected with said second opening, said single first flexible conduitfor when in use, for receiving the moisturized effluent gas, a gas flowalarm connected with said single first flexible conduit, and a singlesecond flexible conduit connected with said gas flow alarm, said secondconduit in fluid communication with said single first flexible conduit,said gas flow alarm for determining the instantaneous pressure or flowvolume of the moisturized effluent gas; said single second flexibleconduit connecting with a pair of spaced apart nasal fittings and, saidgas flow alarm being proximate to said pair of spaced apart nasalfittings to permit the recipient of a moisturizing gas to respond to acondition of said alarm.